<template>
  <div>
    <router-link v-show="absShow" tag="div" to="/" class="header-abs">
      <div class="iconfont header-abs-back">&#xe624;</div>
    </router-link>
    <div class="header-fixed" :style="opacityStyle" v-show="!absShow">
      <router-link to="/">
        <div class="iconfont header-fixed-back">&#xe624;</div>
      </router-link>
      景点详情
    </div>
  </div>
</template>

<script>
export default {
  name: 'DetailHeader',
  data() {
    return {
      absShow: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll() {
      console.log('scroll')
      const top = document.documentElement.scrollTop

      if (top > 60) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = { opacity }
        this.absShow = false
      } else {
        this.absShow = true
      }
    }
  },
  activated() {
    window.addEventListener('scroll', this.handleScroll)
  },
  deactivated() {
    window.removeEventListener('scroll', this.handleScroll)
  }
}
</script>

<style lang="stylus" scoped>
 @import '~style/varibles.styl'
.header-abs
  position absolute
  left .2rem
  top .2rem
  width .8rem
  height .8rem
  line-height .8rem
  text-align center
  border-radius .4rem
  background rgba(0,0,0,.8)
  .header-abs-back
    color #fff
    font-size .4rem

.header-fixed
  z-index 2
  position fixed
  top 0
  left 0
  right 0
  height $headerHight
  line-height $headerHight
  color #fff
  font-size .32rem
  text-align center
  background $bgColor
  .header-fixed-back
    position absolute
    left 0
    top 0
    width .64rem
    text-align center
    font-size .4rem
    color #fff
</style>
